I've been using Taric exclusively for a while now and finally feel like a good player. It's more understanding my opponents than anything else, but that seems pretty obvious. Basically I find out who the best player on my team is and support them from mid to late game.
I've been getting better at setting up and communicating ganks without exposing myself to getting killed in the set up.
I use a full tank build, currently level 17 and no runes since I'm saving for the Tier 3 ones. Taric is very effective, especially if people let me have the golem buff for huge group battles.
This game is so ridiculous for noobs. I've had experience playing LOL beta and lots of HON/DOTA (so I'm familiar with last hitting, warding, creeps, team balance, casters/tanks/carries, etc) and I feel horribly disadvantaged because of lack of runes (and abilities+talents). My friend is obsessed and I just don't see it. I wish he spent his time getting good at Starcraft instead =(.
You usually get put up against people in your bracket so not a lot of people have a huge advantage on you unless you group with a lvl 30 or something.
Runes/Masteries aren't a big deal since actual gameplay is always the deciding factor in low-mid level LoL games.
It's mostly a game of discipline at the beginning. Noobs are usually eager to attack heroes while veterans sit back and just last hit and level until their opponents make a mistake.
Also, greed gets the best of my teams when they stick around after we down a tower or finish a team battle. It's so much easier if you just retreat, recharge, item, and regroup for the next battle but they stay and die a lot.